Malicious Office (OOXML) / .XLSX — malware analysis report

Static analysis result for SHA-256 1226832925973240…

MALICIOUS

Office (OOXML) / .XLSX

362.1 KB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 12.0000
MD5: d53f0f9745ae7d49050e152b64fa7c00 SHA-1: ad40eb1d05440e007aabca028947482e54848871 SHA-256: 12268329259732402322152384100abea2fcb4e63c5b030cf85702ef44cf0457
110 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The sample is an Excel file containing an embedded OLE object, specifically identified as a Microsoft Equation Editor object. Heuristics indicate this object is anomalous and exploits CVE-2018-0798, a vulnerability in Equation Editor that allows for arbitrary code execution. The presence of a hidden worksheet further suggests an attempt to conceal malicious activity. The benign URLs extracted are likely unrelated to the malicious functionality.

Heuristics 5

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/oleObject1.bin contains the Equation Editor CLSID, the legacy component exploited by CVE-2017-11882, CVE-2018-0802, and CVE-2018-0798.
  • CVE-2018-0798 — anomalous Equation Editor native stream high CVE likely CVE_2018_0798_EQUATION_NATIVE_ANOMALY
    Embedded Equation Editor OLE data contains anomalous native stream bytes consistent with a CVE-2018-0798-style Equation Editor exploit. This is treated as likely CVE evidence because the Equation object is malformed and payload-like, but it does not match the exact public matrix-overflow byte signature.
  • Embedded OLE object medium OOXML_OLE_OBJECT
    Document contains an embedded OLE object
  • Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET
    Excel workbook contains 1 hidden sheet(s) — hidden sheets are commonly used to conceal macro code, staging data, or intermediate payload construction
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/sType/ResourceRef#

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
ooxml_oleobject_00.bin
6e55257efa81f785773723e761e9832d8588a8a95cf65d4ac69f8626959771b7		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject1.bin 4096 bytes
ooxml_oleobject_00_ole10native_00.bin
a41587339949a09e197cff064e4c6151dd392be4b0688a8d00cc2ee4f9418556		 ole-package OOXML xl/embeddings/oleObject1.bin Ole10Native stream: ole10NAtiVE 1664 bytes
ooxml_oleobject_01.bin
266f50c77d9265853d59cc53a63da2ee9cadf73c03fd177721c3d0f5c3119713		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/Microsoft_Office_Word_Macro-Enabled_Document1.docm 28352 bytes
emf_00.emf
dd859c27cc8ca6f0696700b0d31101a2005a83280ea277b3af34fd1f4fc1f774		 ooxml-emf OOXML EMF part: xl/media/image8.emf 498420 bytes

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